SEATTLE – Marathoners may not be the only ones huffing and puffing this weekend. Drivers could experience the same symptoms in the form of frustration if they do not plan ahead. Weekend-long construction closures will take place on state routes 99 and 520. The Rock ‘n’ Roll Marathon and the Fremont Fair will also add extra congestion in the Seattle area.

SR 99 lane closure detailsThe northbound lanes of the SR 99 through Seattle will close this weekend between South Spokane Street and Valley Street. This closure includes the Alaskan Way Viaduct and the Battery Street Tunnel.

The northbound closure is needed for the final re-route of the temporary roadway near Seattle’s stadiums. This will allow for further construction of the roadways leading into and out of the new SR 99 tunnel.

The northbound lanes will close at 10 p.m. Friday, June 20, and reopen at 5 a.m. Monday, June 23, in its new configuration (pdf 769 kb).

Additionally, one southbound lane north of the Battery Street Tunnel between Republican and Thomas streets will be closed from 4 p.m. Saturday, June 21, through 5 a.m. Monday, June 23, for utility work.

SR 520 closure detailsSR 520 will close for weekend construction at 11 p.m. Friday, June 20, between Montlake Boulevard and Interstate 405. The highway will reopen at 5 a.m. Monday, June 23.

During the closure, contractor crews for WSDOT’s SR 520 Bridge Replacement and HOV Program will work around the clock to place up to 10,000 tons of asphalt on the highway’s eastbound lanes from Evergreen Point Road to I-405. Contractor crews will also pour concrete for additional sections of roadway deck on the new West Connection Bridge, which will link SR 520’s new floating bridge with the highway’s existing lanes in Seattle.

The following weekend, Friday, June 27, to Monday, June 30, SR 520 will be closed for annual maintenance.

Rock ‘n’ Roll Marathon closure details Approximately 25,000 participants will take part in the Rock ‘n’ Roll Seattle Marathon and Half Marathon beginning at 7 a.m. Saturday, June 21. The event starts and ends at Seattle Center and will close the following sections of Interstate 90 and Interstate 5: • I-90 express lanes will close from 3 a.m. to 2 p.m. • The left lane of the I-5 express lanes and the ramp to Cherry/Columbia and 5th Avenue will close from 8 to 10 a.m. • I-5 mainline ramp closures: o Southbound off-ramp to Dearborn will close from 5 to 9:45 a.m. o Northbound off-ramp to Dearborn will close from 5 to 9:45 a.m. o Dearborn on-ramp to northbound I-5 will close from 5 to 9:45 a.m.

Heaviest traffic times WSDOT traffic engineers want drivers to understand when and where they can expect the most congestion over the weekend. Saturday, June 21: • Northbound I-5 from Boeing Field to SR 520 will have the heaviest traffic from 9 a.m. to 3 p.m. I-5 express lanes will be southbound from 8 a.m. to 1:30 p.m. • Southbound I-5 from Northgate to downtown Seattle will have the heaviest traffic from 2 to 6 p.m. The I-5 express lanes will be northbound from 1:45 to 11 p.m. Sunday, June 22: • Drivers can expect extra congestion on I-5 throughout the day, however, traffic will not be as severe as Saturday due to the marathon.